In several electronic devices, touch screens are used to replace the mouse and the keypad, for example. The user issues commands to the device by touching objects visible on the touch screen. The ability to lock the device or its user interface to prevent unintentional functions, for example, is also known in several devices comprising some sort of a screen. In this case, the keypad does not receive the usual keystrokes, and in devices having a touch screen, the display does not respond to the usual touches. A lock state is thus used to prevent the operation of the device when the touch screen or keypad is subjected to unintentional keystrokes for instance during transport or caused unintentionally by the user. A lock state is also used to prevent unauthorized use of the device. A lock state can be activated for instance by depressing a given key(s) on the keypad or by selecting said function from menus on the touch screen. To deactivate the lock state, the user typically has to enter the right password or key combination.
It is also usual for the touch screen to automatically enter a so-called screensaver state when the device is not used for a given time. When in the screensaver state, the touch screen may display so-called screen saver information, such as news reviews via an Internet connection. The screensaver state ends when the user touches the display or the keypad or moves the mouse, for example. However, to prevent unauthorized use of the device, for example, a special screensaver password may be taken into use, and the user has to enter it for instance via the keypad to deactivate the screensaver state.
The drawback in prior art solutions is the difficulty in remembering special passwords to deactivate a lock state or the corresponding screensaver state. In addition, the use of passwords is especially hard for certain user groups, such as the elderly and handicapped. Furthermore, when for instance a person, who is authorized to use the device but is not the person who specified the password, wants to use the device, he has to know the password. If, again, no screensaver password is required to deactivate the screensaver state, the device may be subjected to unauthorized use or be activated unintentionally during transport, for example. Further, a separate input device, such as a keypad or a writing pad, is required for inputting passwords, which may complicate the use of a device having a touch screen.